Those pulleys can be kinda expensive; about $230. If the rust is only surface rust, i'd go to work with a wire brush on a drill and a can of spray paint. Just a thought. Its a cheap fix and it sure wont hurt to spent $10 on a wire brush and some spray paint to at least give it a shot.
For that alternator, i bet its still got some life left in it. Take it to an alternator shop and get it rebuilt with new bearings and cleaned up. They'll be able to tell you if it works also.